Sam owns a yogurt drink van. She is buying yogurt from a supplier for 0.50 per bottle and sells for 0.60 per bottle. This is the only product Sam sells. Sam pays 100 for insurance per week and she takes a salary of 100 per week. Assume Sam has no other costs to cover. It of What is the contribution per unit? A. 50p B. 60p C. 10p D. zero